1. Field of the Invention:
The present invention relates to a cloth presser device in an industrial sewing machine.
2. Prior Art:
an industrial sewing machine having a head on which a processed cloth is moved corresponding to predetermined various stitching patterns must allow the processed cloth to be moved freely when the needle is lowered and must prevent the processed cloth from rising upward when the needle is raised. To meet these requirements, the industrial sewing machine normally employs a cloth presser mechanism for pressing the processed cloth during the period when a needle starts to penetrate into and casts off the processed cloth.
In a prior art cloth presser mechanism of this type, a cloth presser supported by an arm of a sewing machine is moved vertically while interlocking with a needle bar movable vertically to restrain the processed cloth from rising upward. More particularly, the prior art cloth presser mechanism employs a pivotable lever pivoted directly by a vertical movement of the needle bar and a link mechanism movable vertically along a cam surface of a cam provided on the pivotable lever for vertically driving the cloth presser.
However, in the prior art cloth presser mechanism, a rotary angle of the pivotable lever is determined by the distance of the vertical movement of the needle bar. As a result the rotary angle of the pivotable lever is limited in such manner that the operation of the cloth presser cannot be stopped because the cam surface even when modified in shape will not produce the control desired. Consequently, the prior art mechanism does not function properly.
In order to solve this problem, a more complex link mechanism has been developed for holding the cloth presser at the lowest position for a long period of time. However, even when such complex link mechanism is employed in the industrial sewing machine, an unpleasant striking noise is generated because of contact between a pin and the cam surface.